The use of valves to control the flow of a fluid within an overall heat exchange circuit within an automobile system is known. Control valves or thermal by-pass valves (TBV) are often used in combination with heat exchangers to either direct a fluid to a corresponding heat exchanger for heating or cooling, or to direct the fluid elsewhere in the heat exchange circuit so as to by-pass the heat exchanger under conditions where the heat transfer function of the heat exchanger is not required or is only intermittently required. Control valves or thermal by-pass valves are also often used in automobile systems to sense the temperature of a particular fluid so as to either direct it to an appropriate heat exchanger in order to assist with either (i) maintaining an automobile system fluid within an optimal temperature range or (ii) bringing the temperature of the automobile fluid to within the optimal operating range, for example.
Control valves or thermal by-pass valves are often incorporated into a heat exchange system by way of external fluid lines that are, in turn, connected to an inlet/outlet of a heat exchanger, the control valves being separate to the heat exchanger and being connected either upstream or downstream from the heat exchanger within the external fluid lines. In some applications, multiple control valves or thermal by-pass valves are used in combination in order to achieve a particular control sequence to effectively dictate the fluid flow through the overall heat exchange circuit to ensure that the fluid is directed to the appropriate heat exchanger or automobile system component under the various operating conditions.
Current mechanical thermal by-pass valves typically have two operational states, e.g. either “on” or “off”, with incremental or staged actuation of a single valve being difficult to achieve with mechanical actuation mechanisms. Combining and interconnecting various individual valves in order to achieve a particular actuation sequence can add to the overall costs associated with the automobile system and can also give rise to multiple potential points of failure and/or leakage. Space and or size constraints for a particular system may also be hindered by requiring multiple individual valves that act in combination in order to achieve a desired operation or control sequence. Accordingly, a single by-pass valve capable of providing multiple operational states and responding to various operating conditions by actuating at a first predetermined temperature and again at a second, different predetermined temperature, for example, may contribute to overall cost savings, space savings, weight savings and/or operational efficiencies and are, therefore, desirable.